Enhancing Charge Separation through Oxygen Vacancy-Mediated Reverse Regulation Strategy Using Porphyrins as Model Molecules

Dan Yin; Xingming Ning; Ruizhong Zhang; Peiyao Du; Dongxu Zhang; Yang Deng; Jia Liu; Qi Zhang; Zhen Zhang; Xiaoquan Lu

doi:10.1002/smll.202001752

Enhancing Charge Separation through Oxygen Vacancy-Mediated Reverse Regulation Strategy Using Porphyrins as Model Molecules

Small. 2020 Oct;16(40):e2001752. doi: 10.1002/smll.202001752. Epub 2020 Sep 15.

Authors

Dan Yin¹, Xingming Ning¹, Ruizhong Zhang¹, Peiyao Du^{1

2}, Dongxu Zhang¹, Yang Deng¹, Jia Liu¹, Qi Zhang¹, Zhen Zhang¹, Xiaoquan Lu²

Affiliations

¹ Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, School of Science, Tianjin University, Tianjin, 300072, P. R. China.
² Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730070, P. R. China.

PMID: 32930502
DOI: 10.1002/smll.202001752

Abstract

Highly efficient charge separation has been demonstrated as one of the most significant steps playing decisive roles in enhancing the overall efficiency of photoelectrochemical (PEC) processes. In this study, by employing 5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin-Ni (NiTCPP) as a prototype, an oxygen vacancy (Vo)-mediated reverse regulation strategy is proposed for tuning hole transfer, which in turn can accelerate the transport of electrons and thus enhancing charge separation. The optimal NiO/NiTCPP system exhibits much higher (≈40 times) photocurrent and longer (≈13 times) lifetime of charge carriers compared with those of pure NiTCPP. Furthermore, the electron transfer kinetic rate constant (K_eff ) is quantitatively determined by an efficient scanning photoelectrochemical microscopy (SPECM). The K_eff of the optimal system has a 5.7-fold improvement. In addition, the similar enhancement in charge separation from other semiconductors (CoTCPP and FeTCPP) are also observed, indicating that the Vo-mediated reverse regulation strategy is a promising pathway for tuning the properties of light harvesters in solar energy conversion.

Keywords: charge separation; oxygen vacancy; porphyrin; reverse regulation.

Publication types

Research Support, Non-U.S. Gov't